Anyone tried powering up the BionX with a pair of dyno hub + phase up transformer circuit?

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Last seen: 2 years 10 months ago
Joined: Friday, July 3, 2009 - 08:03
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Anyone tried powering up the BionX with a pair of dyno hub + phase up transformer circuit?

Yes, that's my plan for near future.
I'm planning to build my own frame to use two wheels on the front, and the 26" BionX on the rear
it'll be similar to a Recumbent, but opposite, as the pedalling will be done at the back of the bike
it's like an inverted Recumbent, the riding position is like some one reclining forward with the belly facing down.

if you have seen one of those really weird computer chairs, you'll know what i mean

it's basically going to look like a motorcycle rider, but pedalling.
as i want to put up some sort of clear view shielding in the front very much like the motorcycle to create a better aero bubble, as well as not have to deal with anymore car/truck splashing nasty road water onto your face in middle of a rain storm.

Anyways back to the actual topic...

so a typical dyno hub, say for example the Shimano DH-3N80, which is widely available, and easy to use + low drag.
produces 6V 3W of energy, which is aprox 500mA of power.

there are many many ways (circuits) to UP convert power from low to high, and vice versa.

At first i was planning to just do that on my current bike, but i though "heck if gonna do that, might as well go full throttle into it instead"
meaning build a frame from grounds up, and make a real e-bike, with solar panels, energy recycling, kinetic energy, etc... the full load.

and make the frame as comfortable for me as possible, in reference to the partial shell for the aero bubble.

so it might weight a bit, i'll try to use the lightest material possible, but strong and not fragile at the same time.
even if i can afford custom carbon, i would not go for it, as they are totally worthless, i've seen so many carbon bike break apart after a crash, it's not funny.

my goal to keep the new bike around the 50lb or under, my current one is already 55lb
heck just the BionX kit itself is 17lb, so i want to shave off the battery (8 lb) using the dyno build.

8 lb = lots of electronics i can pack into the bike.

solar panels are flexible now in days, easy to install and light, a bit costly though.
dyno hubs are relatively light, taking 2 wheels into consideration, that is still lighter than packing up an 8 lb battery.
electronics and circuit boards... they are waaaay light, even if i had to make a 4 phase converter.

so not taking any of the extra power into account, just with the 2 dyno hubs, if i pair them up in series i should be able to produce 12V 6W with 1A of power.

The BionX wheel uses average 350W and requires 36V to push it?
then that means i still have to make a conversion of 24V and 344W...

according to info from this

and according to the circuit samples on

the idea is not too hard, as i've already seen some other ebikers without battery, and only using just 1 dyno hub to power up the rear motor, however on those setups they use a lower power motor like the 250w BionX for example.

also i'm pretty sure some of my math is wrong, as it's based on the manufacturer specs, but not actual required power/volt/watt required to run the wheel.

That's where i could use some help, on information about the actual voltage requirement, power consumed, and wattage required.

Then i can properly design the circuit that works best for my project.

I want to get the electronic stuff figured out, before i even begin the frame building and design process.

If this is not gonna work, then it's pointless to build the frame.

However if this works... i'll be placing my order for the BionX 500W wheel next :D

ashby3's picture
Last seen: 14 years 2 months ago
Joined: Tuesday, March 31, 2009 - 13:44
Points: 35
Re: Anyone tried powering up the BionX with a pair of dyno ...

This is a joke - Right?

If not let me enlighten you.

First one cannot run a Bionx wheel with out the control console and current regulating circuits which are located in the battery unless you plan to design and build your own replacements for them. The Bionx motor is essentially a large and powerful stepper motor. Stepper motors have been is use for years in things like computer printer and plotters. They are not like the motors must of us know where one puts power on to a pair of wires and they turn. Stepper motors have more than a pair of wires and move by having a short pulse of electricity of the correct voltage and frequency with sufficient current applied to the right set of poles and it then move a fixed amount. This fixed amount of movement is called a step. These motors have three, four and even five sets of poles - coils of wire wrapped around a medal shaft that work together. By controlling the voltage and current while changing the frequency of the pulses applied to sets of poles the speed at which the motor turns can be controlled.

You can not use a dynamo attached to a wheel on your trike to generate power to run a motorized wheel on the trike. The resistance created in the dynamo by the magnetic line of force when they cut through the coils of wire in the dynamo, which is how it creates electricity, will be much greater than the amount of usable power one would get from them. It would be the same as attaching a dynamo to the Bionx wheel and excepting it to power it self. Where you put the dynamo on the trike does not matter. One can not get something for nothing.

One cannot at this time get away from having a battery - solar cells are a somewhat but not inexpensive way to enhance the available power but they do not produce power at a constant enough rate to be used with out some sort of battery to make up the different also when it happens that the solar cell are producing more power than the system is consuming there has to be somewhere for the power to go so when one has stopped for some reason they can charge the batteries. To my knowledge there is currently no way to charge the Bionx battery with solar cells but I wish there was and I may explore this someday.


Last seen: 2 years 10 months ago
Joined: Friday, July 3, 2009 - 08:03
Points: 16
Re: Anyone tried powering up the BionX with a pair of dyno ...

this is part of the circuit i have in mind.

no i'm not attaching the dynamo to the motor per say.

and yes, the goal here is to replace the battery as mentioned on my original message, to shave off some weight.

That's why i'm trying to calculate what is the actual load on the battery on a flat, then i can adjust accordingly.

the original BionX circuit will be kept, the only thing that changes is the battery itself, so all the regulator, etc, etc, that is part of the BionX battery will remain.
We're simply substituting the battery here.

That's why i want to design a phase convector that is able to adapt to the different stages (steps) of power requirement.

If people have done that already for other eBikes, it can surely be done for the BionX set as well.

Last seen: 5 years 8 months ago
Joined: Monday, June 22, 2009 - 12:24
Points: 524
Re: Anyone tried powering up the BionX with a pair of dyno ...

No, you CANNOT power a vehicle from electricity generated by a wheel driven, or wind driven, generator on the SAME vehicle, wherein the energy used to power the generator comes from the forward motion of that vehicle! You will need a BATTERY to power your hub motors! Solar power is nice, but normally the space required to mount the needed panels would be greater than what is available on the vehicle, and aiming them properly for maximum power would be a big problem, as would avoiding shadows. Solar charging is best done at home, or when parked in a clear, sunny area.(A solar array, producing 1,000 watts on a perfect day, would be about 6X20 feet,probably weigh over 300 pounds, and cost at least $4,000.00 U.S.) Such a panel would fully charge a fully discharged VECTRIX scooter in about 2 days, on average. (You would also require a battery storage bank, and an inverter, to change the variable solar power into steady A.C. power, to operate the vehicle battery charger, and this would cost MORE money!--There is no "Free Ride", or perpetual motion, with excess energy!--Bob

Robert M. Curry

ashby3's picture
Last seen: 14 years 2 months ago
Joined: Tuesday, March 31, 2009 - 13:44
Points: 35
Re: Anyone tried powering up the BionX with a pair of dyno ...

Voltage doubling circuit have been around for years but what you may not understand is if you use one to doubles the voltage one will end up with less than half the current one started with. So if one starts with 6 volts and runs it through a number of voltage doubling circuits to get 36 volts and one needs let us sat 3 amps of current to run the motor and since there is some current lose in these circuits one will need to start with about 12 amps of current at 6 volts - will ones dynamo produce that much current - I do not think so and if they did they would likely require a lot more horse power then I could produce pedaling my trike.

Also with out a battery how will one keep the console and regulator circuits of the Bionx system up and running every time the wheels stop. Even if one could get enough power from the dynamos while pedaling (I do not believe this is possible) every time the trike stopped moving everything would shutdown.

There is no free power - if you try to take power from a moving vehicle you will slow it down. No matter how you try to recover power it will not work. With the exception of solar which gets its power from the sun not the vehicle there is not free power.

When I was young they use to sell a generator power light for bicycle. It worked like this you had a light mounted on the front of your bike and some models had a rear facing light with a red lens attached to the generator. To use the light one flipped a small lever which allowed the generator's axle to rub against the read wheel making it turn and producing electricity to power the light - the light were 3 volts and required about .1 amp to drive and it made riding the bike noticeably more difficulty to ride I can not imagine what producing 12 amps at 6 volts would take.


Boreas's picture
Last seen: 14 years 8 months ago
Joined: Monday, July 27, 2009 - 11:17
Points: 2
Re: Anyone tried powering up the BionX with a pair of dyno ...


I was just wondering if I got it wrong or if the dyno hubs in the front wheels really were to be the only source of power for the motor hub in the rear. If so it seems to me that you're trying to fight the 1st law of thermodynamics: Energy can neither be created nor destroyed. Which basically means that you cannot get more energy from a system than you put into it.

By pedaling you're using your own body to convert the chemical energy from your food into kinetic energy. That's your energy input to the system. That energy is spent to overcome inertia when you accellerate as well as the friction forces that want to stop your trike, or drag. By adding the dyno hubs you're adding another drag force to the system. They will provide drag by trying to convert as much of the trikes kinetic energy as they can into electric energy.

If you could transform the voltage and amps from the dyno hubs to the voltage and amps (= energy) needed to drive the rear hub without loss, then you will get an amount of energy from the dyno hubs equal to the resistance they create to the trike's movement. That energy will be all the energy you'll have to run the motor hub. That means that you'd at best be getting just enough help from the motor hub to counter the drag from the dynos. And that's ideal conditions. I guess that the conversion will not be lossless. You'll have an amount of the energy lost as heat in the system. That means that the total equation will end up negative and you'll get less energy to the motor hub than you'll use to spin those dyno hubs.

Then you'd actually be better off dropping the hub dynos as well as the hub motor. That would mean less drag and less weight, = less energy needed to propel the trike. ;) Of course I could be wrong. In this case I really hope I am. A Perpetuum mobile would be fun, as well as the end of our quest for clean energy. :)

Kind regards.

-"Everyone who believe in telekinesis, raise my hand."

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